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UNITED STATES PATE T Grinch.

HEINRICH VOLLBREOHT AND CARL MENSOHING, OF BUFFALO, NEWV YORK, ASSIGNORS TO THE SOHOELLKOPF ANILIN E AND CHEMICAL COMPANY,

OF SAME PLACE.

NITRONAPHTHOLSULPHONIC ACID.

SPECIFICATION forming part of Letters Patent No. 333,036, dated December 22, 1885.

Application tiled January 13, 1885. Serial No. 152,805. (Specimens) To all whom it may concern:

Be it known that we, HEINRICH VOLL- BREOHT and CARL MENSOHING, of the city of Buffalo, in the county of Erie and State of New York, have invented new and useful Improvements in the Manufacture of Dye-Stuffs or Coloring-Matters, of which the following is a specification.

Our invention relates to the production of anew yellow dye-stuff consisting of a new naphtholmononitromonosulphonic acid. This dye-stuff is produced by the reaction of a nitro compound of our new alphanaphtholdisulphonic acid with carbonate of potash. This I 5 new naphtholdisulphonic acid is produced in the following manner: We mix one hundred parts, by weight, of the lime salt of alphanaphthalinemonosulphonic acid, which acid is made in the well-known manner, with two hundred parts of sulphuric acid of 66 Baum.

We then add to this mixture slowly fortyfive parts of nitric acid of 40 Baum at a temperature of from 90 to 100 Centigrade, whereby two new nitromonosulphonic acids are formed. These acids are converted into their amido compounds by any suitable and well-known method, which conversion results in two new naphthylaminesulphonic acids. These last-mentioned acids are easily separated, owing to the unequal solubility of their salts in water.

The naphthylaminesulphonic acid which forms a sodium salt which is not easily soluble in water is used for producing our new color- 5 producing acid, and is separated from the naphthylaminesulphonic acid which produces a sodium salt easily soluble in water. This naphthylaminesulphonic'acid is converted into the diazo compound by a solution 0 of sodium nitrite, in the following manner: WVe dissolve in two thousand parts of water two hundred and forty-five parts of said noteasily-soluble sodium salt of naphthylaminesulphonic acid, and add to this solution two hundred and fifty parts of sulphuric acid of Baum. We then cool the solution to 6 centigrade, and add slowly a solution containing sixty-nine parts of sodium nitrite in six hundred and ninety parts of water.

While this solution is added the diazo compound is deposited'in the form of yellow crystals. The mixture is then allowed to rest for several hours. The diazo compound is introduced into a boiling liquid composed of one thousand parts of water and one hundred and fifty parts of sulphuric acid of 50 Baum, and boiled for several hours, whereby the diazo compound is broken up and a new oxysulphonic acid (naphtholsulphonic acid) is produced. This new naphtholmonosulphonic acid is the raw material for the production of the color-producing naphtholdisulphonic acid.

In producing this naphtholdisulphonic acid we take one part of the above-described naphtholmonosulphonic acid and add to it gradually from two to three parts of sulphuric acid of about 66 Baum. The mass is then heated over a water bath at a temperature of from to centigrade for about one hour, until allthe monosulphonic acid is converted into disulphonic acid, which operation is completed when the mass is entirely soluble in water. The whole is then poured into water, and thesodium salt is produced by any wellknown method.

Our new naphtholdisulphonic acid is an alpha acid, and shows characteristic differences from all hitherto-known naphtholdisulphonic acids-such, for instance, as the beta- 80 naphthol'disulphonic acid describedin Letters Patent of the United States N 0. 210,233, granted to H. Baum, November 26, 187 8, which will not form any nitro compounds.

The herein-described new naphtholdisulphonic acid forms, when treated with nitric acid, a beautiful yellow dye-stuff, which consists of a naphtholmononitromonosulphonic acid, and which forms beautiful dye-stuffs with diazo compoundsfor instance, diazobenzol. This new naphtholmononitromonosulphonic acid cannot be, therefore, confounded with the yellow dye-studs produced by Caro and Levinstein, which consist of alphanaphtholdinitromonosulphonic acids, and do not produce dye-stuffs with diazo compounds.

Our new naphtholmononitromonosulphonic acid stands as to shade between the naphtholyellow made by Caro and Levinstein and the crocein-yellow patented by Bayer. The former is much greener in shade than our yellow, and the latter is much more reddish and not as brilliant. We dissolve one hundred pounds of the sodium salt of our new naphtholdisulphonic acid in two hundred pounds of water. \Ve then add sixty-five pounds of nitric acid of about fiftyfour per cent. strength at a temperature of from 60 to 70 centigrade. After standing about twenty-four hours the nitration is finished. -We then neutralize With carbonate of potash or its equivalent, and our new dye'stuff is precipitated by common salt in the form of a crystalline yellow powder, which is purified by dissolving and reprecipitating it.

The proportion of the ingredients, as also the temperature named in the foregoing de- 

